Space telegraphy.



No. 768,001. PATENTED AUG. 16, 1904.

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W J z /lowxa /ma- UNITED STATES Patented August 16, 1904;

PATENT OF ICE.

JOHN STONE STONE, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO WILLIAM W.SWAN, TRUSTEE, OF BROOKLINE, MASSACHUSETTS.

SPACE TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 768,001, dated August16, 1904. Application filed February 23, 1904. Serial No. 194,651. (Nomodel.)

ticularly to systems for selectively receiving.

signals transmitted by such waves of predetermined electrical frequencyand of predetermined group or wave-train frequency.

Systems for selectively receiving signals transmitted by electromagneticwaves of a predetermined group or wave-train frequency have long beenwell known. In most of these systems the selective agent is either amonotelephone or an electromagnet provided with a reed-armature attunedmechanically to the group or wave-train frequency of the waves by whichthe signals are transmitted. In some cases, however, it has beenattempted to attune a local receiving-circuit by means of coils andcondensers to such group or wave' train frequency; but I know of no casein which an operative system has been produced, because in every case,so far as I am aware, the condenser which forms one of the tuningelements of the local tuned receiving-circuit is included in series withthe battery,'the wave detector or receiver, and the signal-indicating.

device.

It is the object of my present invention to provide a space-telegraphreceiving system in which a local receiving-circuit may be attunedelectrically by capacity and inductance to a predetermined group orwave-train frequency, and such local receiving-circuit so attuned maywith advantage be used in conjunction with a resonant circuit attunedtothe electrical frequency of the waves the energy of which is to bereceived.

My invention may best be understood by having reference to the drawingswhich accompany and form a part of this specification and whichillustrate diagrammatically four simple embodiments of my invention.

In the drawings, Figures '1, 2, 3, and 4t represent in diagram fourforms of apparatus and circuit arrangements constituting spacetelegraphreceiving systems to which my invention has been applied. In thefigures, V is an elevated conductor. E is an earth connection. Mis atransformer, preferably a step-down transformer. 0 C1 are condensers.LL1 are inductances. L L are impedances. L L" are choking-coils. R is aresistance. B1 is a battery. B B are bolometers or otherelectroreceptive devices adapted to utilize in their operation thedissipative energy of the electrical oscillations developed in thecircuits in which they are included.

T is a signal-indicating device, which may be a telephone or amonotelephone or an electromagnet whose reed-armature is attunedmechanically to the group or wave-train frequency of theelectromagnetic. waves, to the electrical frequency of which theresonant circuit M C B L is attuned to respond, being the group orwave-train frequency to which the local receiving-circuit B (J1 T L1 isat tuned. The circuits l\I CB L and M G B L are resonant circuitsattuned to the electrical frequency of the electromagnetic signalwavesthe energy of which is to be received and adapted to absorb the energyof electrical oscillations of correspondingfrequency to the practicalexclusion of electrical oscillations of other frequencies. Suchaselective receiving system has been described in my Letters Patent No.714:,756, dated December 2, 1902, to which reference may be had for amore complete description of the construction of parts and the mode ofoperation thereof than is necessary to set forth herein.

In Fig. 1 a bolometer B is shown serially connected in the resonantcircuit M C B L, and inasmuch as the fine wires or strips 1 2 3 4 ofsaid bolometer form a balanced Wheatstones bridge the localreceiving-circuit containing the signal-indicating device T may beconnected directly to the equipotential points of this bridge; but inFigs. 2 and 3the choking-coils L L are preferably included in the localreceiving-circuit between the signalin-,

dicating device T-and the bolometer B, which in these cases consists ofa single fine wire or strip 1. I

In order to utilize the principle of group or wave-train frequencytuning,vit is desirable that the wave detector or receiver'employed beself-restoring, and although other forms of wave-detector of the coherertype may be used, as I have pointed out in my applications Serial Nos.182,637 and 182,629, both filed November 25, 1903, I find it moreadvantageous to employ a receiver which utilizes in its operation thedissipative energy of the electrical oscillations developed in thecircuit in which it is included, because such receivers are moresensitive and are more certain and reliable in their action thanreceivers of the coherer type.

The circuits B C1 T L1 and B C1 T L1 in Figs. 1, 2, and 3, respectively,and the circuit C1 L1 T in Fig. 4 are resonant circuits at tuned to thegroup or wave-train frequency of the electromagnetic waves the energy ofwhich the resonant circuit M C B L is designed to selectively receive.

The operation is as follows: When electromagnetic signal-waves, to theelectrical frequency of which the resonant circuit M C B L is attuned,impinge upon the elevated conductor V, the said resonant circuitresponds strongly to the resulting electrical oscillations, which areconveyed thereto by means of the transformer lVI, although, if desired,the elevated conductor may be conductively connected to said resonantcircuit. The amplitude of these oscillations is greatly increased by theresonant circuit, and the dissipative resistance of the electroreceptivedevice B is varied by the energy of said oscillations. This variationin'the dissipative resistance of the electroreceptive device B will beperiodic and the number of variations per unit of time will be equal tothe number of groups or wave-trains of electromagnetic waves developedin said unit of time at the distant transmitting-station. This periodicrate of variation in the dissipative resistance of the electroreceptivedevice B produces a corresponding rate of variation in the potentialdifferonce at the points where the impedances L L are connected with thecircuit B C1 T L1, and if said circuit be attuned by the condenser ()1and the coil L1 or by other means to a frequency corresponding to suchrate of variation a maximum current will be developed in said circuitand a maximum response of the telephone T will be effected.

7 It will be observed that the circuit L L, containing the source ofelectromotive force B1. is connected in parallel with the circuit B C1 TL1. If, however, the battery B1 be included in series with the receiverB, condenser C1, signal-indicating device T, and coil L1,.

no amount of variation in the resistance of the receiver B will effectthe slightest variation in the electromotive force in the battery B1,and inasmuch as a condenser is not transparent to steady orunidirectional electric currents no current flow will be producedthrough the telephone T.

As indicated at A in Fig. 2, a source of rapidly-varying electromotiveforce may be employed, especially where the signal-indicating device Tis not mechanically attuned. A continuous note is thereby produced inthe telephone, and the variations in the resistance of the receiver Bwill effect variations in this note. It is not necessary, however, whena source of rapidly-varying electromotive force is employed to connectthis source to a circuit in parallel with the local resonantreceivingcircuit B C1 T L1, because in this case said source 'may beserially connected with the circuit, as indicated iIrFig. 3, inasmuch asa condenser is transparent to rapidly-varying currents. In this case acertain portion of the rapidly-varying current will pass through theresonant circuit C RI L B; but inasmuch as the capacity of the condenserC is relatively small compared with the capacity of the condenser C1 thegreater portion of this current passes through the circuit B L1 T (J1,producing a continuous note in the telephone T, which note is variedwhen the resistance of the receiver B is changed by the electricaloscillations absorbed by the circuit C M L B.

In Fig. 4 the resonant loop-circuit C1 L1 T. attuned to a definite groupor wave-train frequency, is serially included in a circuit containingthe receiver B, the choking-coils, and a source of electromotive force.Here, again, if the circuit C1 L1 T be attuned to a frequency equal tothe rate of variation of the resistance of the bolometer B a maximumcurrent is developed in said circuit and a maximum response of thesignal-indicating device T is effected.

1. Inaspace-telegraph receivingsystem, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or wave-train frequency of saidelectrical oscillations, and a signal-indicating device associated withsaid local receiving-circuit.

2. Inaspace-telegraph receivingsystem, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or wave-train fre quency of saidelectrical oscillations, a signalindicating device associated with saidlocal IIO receiving-circuit, and a source of electronictive forceconnected in parallel with said local receiving-circuit.

3. Inaspace-telegraph receiving system, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or Wave-train frequency of saidelectrical oscillations, a signalindicating device associated with saidlocal receiving-circuit, and a source of rapidly-varying electromotiveforce operatively connected with said local receiving-circuit.

4. Inaspace-telegraph receiving system, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or Wave-train frequency of saidelectrical oscillations, and a signal-indicating device mechanicallyattuned [SEAL.]

to said group or wave-train frequency associated with said localreceiving-circuit.

5. lnaspace-telegraph receiving system, an elevated receiving-conductor,a resonant circuit associated therewith and attuned to the electricalfrequency of the waves the energy of which is to be received, and anelectroreceptive device adapted to utilize in its operation thedissipative energy of the electrical oscillations developed in saidresonant circuit, in combination with a local receiving-circuit attunedby capacity and inductance to the group or wave-train frequency of saidelectromagnetic waves, and a signal-indicating device associated withsaid local receivingcircuit.

In testimony whereof I have hereunto subscribed my name this 16th day ofFebruary, 1904:.

JOHN STONE STONE.

Witnesses:

BRAINERD T. JUDKINS, Gr. ADELAIDE HIGGINS.

It is hereby certified that in Letters Patent No. 768,001, grantedAugust 16, 1904, upon the application of John Stone Stone, of Cambridge,Massachusetts, for an improvement in Space Telegraphy, an error appearsin the printed specification requiring correction, as follows: In line13, page 2, the numerals 182,637 should read 182,627 and that saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Ofiice.

Signed and sealed this 11th day of July, A. D., 1905.

F. I. ALLEN,

Commissioner of Patents.

receiving-circuit, and a source of electronictive force connected inparallel with said local receiving-circuit.

3. Inaspace-telegraph receiving system, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or Wave-train frequency of saidelectrical oscillations, a signalindicating device associated with saidlocal receiving-circuit, and a source of rapidly-varying electromotiveforce operatively connected with said local receiving-circuit.

4. Inaspace-telegraph receiving system, an electroreceptive deviceadapted to utilize in its operation the dissipative energy of theelectrical oscillations developed in the circuit in which it isincluded, in combination with a local receiving-circuit attuned bycapacity and inductance to the group or Wave-train frequency of saidelectrical oscillations, and a signal-indicating device mechanicallyattuned [SEAL.]

to said group or wave-train frequency associated with said localreceiving-circuit.

5. lnaspace-telegraph receiving system, an elevated receiving-conductor,a resonant circuit associated therewith and attuned to the electricalfrequency of the waves the energy of which is to be received, and anelectroreceptive device adapted to utilize in its operation thedissipative energy of the electrical oscillations developed in saidresonant circuit, in combination with a local receiving-circuit attunedby capacity and inductance to the group or wave-train frequency of saidelectromagnetic waves, and a signal-indicating device associated withsaid local receivingcircuit.

In testimony whereof I have hereunto subscribed my name this 16th day ofFebruary, 1904:.

JOHN STONE STONE.

Witnesses:

BRAINERD T. JUDKINS, Gr. ADELAIDE HIGGINS.

It is hereby certified that in Letters Patent No. 768,001, grantedAugust 16, 1904, upon the application of John Stone Stone, of Cambridge,Massachusetts, for an improvement in Space Telegraphy, an error appearsin the printed specification requiring correction, as follows: In line13, page 2, the numerals 182,637 should read 182,627 and that saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Ofiice.

Signed and sealed this 11th day of July, A. D., 1905.

F. I. ALLEN,

Commissioner of Patents.

It is hereby certified that in Letters Patent No. 768,001, grantedAugust 16, 1904,

upon the application of John Stone Stone, of Cambridge, Massachusetts,for an improvement in Space Telegraphy, an error appears in the printedspecification requiring correction, as follows: In line 13, page 2, thenumerals 182,637 should read 182,627 and that said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case in the Patent Oflice.

Signed and sealed this 11th day of July, A. 1)., 1905.

[SEAL] F. I. ALLEN,

Commissioner of Patents.

